The use of hybrid molecules in a study of the equilibrium between nerve growth factor monomers and dimers.

摘要: The major protein in beta nerve growth factor preparations, beta1NGF, is a dimer which both peptide chains have COOH-terminal arginine residues. Digestion of beta1NGF with carboxypeptidase B produced dimer, beta3NGF, lack these terminal Exposure mixtures beta1 and beta3NGF dimers to 8 M urea produce monomers, followed by removal allow recombination, resulted the formation hybrid beta2NGF, comprising one arginine-containing arginine-less chain, as well parent dimers. amount three formed was close that expected from random association monomers. Hybrid beta2NGF also where incubated at pH 2.6 4.5. has half-time 6 h 4.0 4 degrees C. Its rate decreased above 4.5, becoming minimal between 9.5 10.5, increased increasing temperature. determined lowest mixture exposed, irrespective its prior history. These data suggest same mechanism absence presence step. An approximate value for Kd, equilibrium dissociation constant monomer derived. 3 - 10(-10) alpha-subunit 7S NGF not only pHs an alphabeta complex stable, but acid no observed sedimentation analysis, suggesting present methodology offers more sensitive probe subunit interactions. In contrast, gamma number indifferent proteins had little or effect on appearance studied.